Roll-on dispensers are very popular for dispensing liquids and to a more limited extent for dispensing powders since the ball or roller acts as an efficient way of distributing the contents of the dispenser over skin or other application surfaces. However, the dispenser has one potential disadvantage. If the closure of the dispenser is not applied properly and tightly, there is a risk of the contents leaking out of the dispenser if it has fallen on its side or if it is a so-called invert dispenser, by which is meant herein a dispenser in which the opening of the dispenser under its normal storage orientation is at the bottom of the dispenser or if an upright dispenser is stored in an invert orientation in order to ensure that its contents is employed to the last drop. It will be recognised that if the closure is not fluid tight, then the fluid contents can flow out. This is both wasteful and potentially messy.
Commonly, the closure for roll-on dispensers comprises a cap which fits over and around the housing for the ball or roller. The cap advantageously has a side-wall so dimensioned and/or an interior wall extending centrally from its closed end which engages the ball or roller and urges the latter towards the interior surface of the housing, closing the gap between the two of them and effecting a fluid-tight fit. This entails moving the cap towards the dispenser, axially, during the securing operation (and herein this is sometimes called downwards) and commonly for roll-on dispensers this is achieved by co-operating screw threads on respectively the interior face of the cap and the exterior face of the housing or bottle. In order to be effective, at least once complete turn of the screw threads around the housing or bottle and the cap is needed, otherwise the cap when fitted does not apply balanced axial forces around the perimeter of the ball, and rocking of the cap on the housing is possible, so that there is a significant risk of leakage from the dispenser. However, if greater than a single turn of screw threads is employed, that too introduces potential difficulties. Most humans are unable to rotate a cap for a complete turn around a dispenser housing, or if they can do so, the rotational force at or approaching the 360 degree point is very weak, whereas it is at that time in the procedure for fitting the cap when the greatest force is needed to tighten the screw. This means that the cap must be released from the hand, the cap hand reoriented relative to the cap, and the rotated further. The dispenser bottle/housing could alternatively be rotated relative to the cap, but the problem is the same. Many humans are rather lazy or in today's world are rushing to save time for activities perceived to be more important than securing a cap onto a bottle. Accordingly, there remains a risk that the consumer will fail to rotate the cap adequately if the cap employs a screw thread. Furthermore, the reverse problem can also arise with screw threaded closures, namely over-threading, because the leading edge of a thread is normally chamfered so as to assist in seating of the thread into its groove. Over-rotation can cause distortion of the cap and with a consequential immediate risk of incomplete closure or of the cap not being properly secured in a subsequent closure.
Roll-on dispensers employing a screw-thread connection between cap and bottle are described in for example in GB 2272186, GB2275024, U.S. Pat. No. 2,968,826, U.S. Pat. No. 6,511,243, WO 00/49908 and WO 00/64302. Such dispensers are commonly available commercially in 2003, ranging from world-wide brands such as Rexona™, Dove™ and Axe™ through to brands available regionally or locally such as own label brands in supermarkets. Dispensers intended for storage in an invert orientation are described in the above-mentioned U.S. Pat. No. 6,511,243 and are commercially available under the brand Avon. However, many existing commercially available roll-on dispensers in June 2004 have been capable of standing in both an upright and invert orientation, such as those under the above-mentioned global brands and Amplex™. All of these employed a screw thread to attach the cap to the dispenser body.
Screw threads are not the only means previously contemplated for attaching a cap to a bottle or jar. An alternative system comprises a so-called bayonet system which employs a plurality of sets of engagement means, each set comprising a bayonet that is rotated into a locking recess in a mating lug. Such a system is described in each of U.S. Pat. No. 4,434,903, U.S. Pat. No. 4,223,795 and U.S. Pat. No. 4,059,198, amongst others, for attaching a cap to upright bottles, sometimes in combination with or in the context of child resistant closures. The bayonet systems disclosed in said patent specifications commonly mount each set of bayonet/lug symmetrically and at the same axial spacing from the respective mouths of the cap and bottle. They can be described as simple multi-start systems. Such an arrangement of bayonets and lugs means that any bayonet can be mated with any lug, which is acceptable if the cap is symmetrical. However, if the cap and bottle exhibit a degree of asymmetry, for example from their shape, pattern, configuration or adornment, such simple symmetry creates the risk of a user replacing the cap in an incorrect orientation.
Although the problem of obtaining a fluid seal preventing egress of liquid by rotation of the cap relative to bottle has been described in the context of a roll-on dispenser, it will be recognised that a similar seal is needed if an alternative flow regulator were to be employed.
A further possible complication is that designers of cosmetic dispensers are seeking ways to differentiate their containers from those of competitors. This assists in product recognition and assists the customer to select the same product again if he or she has been satisfied by its performance. One way of achieving packaging distinctiveness is by creating a less symmetrical shape for the dispenser and a corresponding shape for the cap. In order to preserve the integrity of such a design, the cap needs to fit on the dispenser in a unique orientation.
Accordingly, it would be desirable to devise a means of securing a cap onto a dispenser for a hand-held cosmetic fluid which avoided one or more of the risks or disadvantages associated with a conventional screw thread mounting means but at the same time ensured a desired orientation of the cap relative to the bottle of dispenser.